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Wysokie temperatury w pracy. Wytyczne dla pracodawców (Przewodnik UE)

Żubrzak Jacek

Przegląd Papierniczy

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2023

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R. 79, nr 12

640--642

PL

Powodem powstania artykułu było opublikowanie w bieżącym roku Przewodnika Unii Europejskiej na temat warunków pracy w wysokich temperaturach [1]. Omawiane kwestie dotyczą wszystkich pracodawców, zatem mogą być przydatne również w naszej branży.

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Upały a prawo pracy

Żubrzak Jacek

Przegląd Papierniczy

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2023

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R. 79, nr 7

385--386

PL

Obciążenie organizmu pracą w warunkach wysokich temperatur, utrzymujących się w miesiącach letnich, znacznie wzrasta. Z jednej strony wpływa na obniżenie wydajności, z drugiej przyczynia się do wypadków przy pracy. Przepisy BHP mówią jedynie o maksymalnej temperaturze, powyżej której pracy nie powinni wykonywać młodociani i kobiety w ciąży. Określają jej poziom maksymalny na 30°C w pracy biurowej. Pracodawcy jednak nie są zwolnieni z obowiązku zapewnienia odpowiednich warunków. Jeżeli nie są one spełnione, pracownik ma prawo odmówienia wykonywania swoich obowiązków.

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Shock Ignition and Growth of HMX-based PBXs under Different Temperature Conditions

Liu Rui, Han Yong, Li Ming, Jiang Zhihai, He Songwei

Central European Journal of Energetic Materials

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2019

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Vol. 16, no. 1

21--32

EN

The Lagrange test was conducted to investigate the shock ignition and growth of HMX-based polymer bonded explosives (PBXs) under different temperature conditions. In this study, three temperature conditions, 25 °C, 80 °C and 120 °C were used. The pressure history values along the direction of the detonation wave propagation were obtained and presented as the characteristics of the shock ignition and growth. Manganin piezoresistive pressure gauges were used to measure the pressure. The results showed that the distance to detonation was clearly reduced as the temperature was increased. A distance greater than 9 mm at 25 °C was changed to less than 3 mm at 120 °C. In order to understand this phenomenon in more detail, the Lee-Tarver ignition and growth model was employed to simulate the Lagrange test, and the simulated pressures were compared with the measured pressures. The results demonstrated that the intrinsic mechanism of the phenomenon was that the high temperature changed both the equation of state of the unreacted explosive and the chemical reaction rate. It was remarkable that the parameter R2 in the model was reduced from −0.05835 to −0.06338, and the parameter G1 in the model was increased from 1.3 to 2.12.

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Modification of Surface of Basalt Fabric on Protecting Against High Temperatures by the Method of Magnetron Sputtering

Miśkiewicz Pamela, Frydrych Iwona, Pawlak Wojciech, Cichocka Agnieszka

Autex Research Journal

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2019

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Vol. 19, no. 1

36--43

EN

Basalt fibers and fabrics made of these are characterized by excellent thermal and mechanical properties. Therefore, basalt fabrics, due to a good resistance to high temper atures, are frequently applied in the personal protection equipment (PPE). In order to improve their thermal properties and, above all, the contact heat resistance, the process of physical vapor deposition was proposed. The process of Physical Vapor Deposition (PVD) involves producing a coating on a specific substrate as a result of physical deposition of molecules, ions or atoms of the selected chemical compounds. The method selected for the test is the magnetron sputtering. It involves depositing a uniform film of chromium on the surface of the basalt fabric. In order to improve the thermal properties – especially the contact heat resistance, two values of thickness of the chromium layer deposited on the basalt fabric surface were adopted for the test. Covering 1 μm and 5 μm with the chromium layer did not fulfil the expectations and the research will be continued.

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The influence of boundary conditions on the safety of steel trusses subjected to high temperatures

Kubicka K., Radoń U., Szaniec W.

Structure and Environment

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2017

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Vol. 9, no. 4

229--240

EN

The study provides an analysis of three trusses that differed only with respect to support. All trusses were analysed for normal and accidental design cases, latter under fire load. A standard fire curve was adopted, and it was assumed that all the elements were heated from all sides. Using the MES3D program, temperature increase in bars, values of displacements and those of axial forces were determined for all structures in the successive minutes of the fire. The state of stress and displacement in the successive minutes of fire was discussed.

PL

Artykuł dotyczy analizy trzech kratownic, różniących się między sobą sposobem podparcia. Wszystkie kratownice zostały przeanalizowane w normalnej sytuacji projektowej oraz podczas pożaru. Zastosowano krzywą pożaru standardowego i założono, że wszystkie elementy są ogrzewane z każdej strony. W kolejnych minutach trwania pożaru obliczono wzrost temperatury w prętach kratownicy, przemieszczenia węzłów oraz siły osiowe. Do obliczeń wykorzystano program MES3D. Omówiono stan naprężeń i przemieszczeń w kolejnych minutach pożaru.

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Combined effect of silica fume and additive on the behavior of high performance concretes subjected to high temperatures

Tebbal N., Rahmouni Z., Maza M.

Mining Science

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2017

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Vol. 24

129--145

EN

This study examines the effect of the additions of silica fume and super plasticizer on the mechanical performance of high performance concretes at high temperatures. The tested concretes are formulated with 5% silica fume and two dosages of super plasticizers in the ratio of (2%, 2.5%) the weight of cement after having been exposed to four maximum temperatures, 200 °C, 400 °C, 600 °C and 900 °C without intermediate level, for a ripening cycle 24 hours in total. The results obtained show that the mechanical resistance at 28 day increases with the degree of temperature compared to that measured at 20 °C. On the contrary, a clear decrease is observed between 600 °C and 900 °C. However, material composition seems to have great influence on the mechanical strength.

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The Attempt of the Low-Cycle Fatigue Life Description of Chosen Creep-Resistant Steels Under Mechanical and Thermal Interactions

Okrajni J., Marek A.

Archives of Metallurgy and Materials

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2017

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Vol. 62, iss. 4

2349--2353

EN

The study focuses on the problem of determination of low-cycle fatigue properties for the chosen group of creep-resistant steels used in the power and chemical industries. It tries to find the parameter which would describe well the fatigue life and take into account mechanical loads and temperature. The results of LCF tests have been presented in the paper. New parameter P has been introduced. This parameter joins a plastic strain range, a stress range and temperature. The fatigue life has been predicted versus parameter P. The comparison of the predicted and observed values of fatigue life shows the agreement between these values. The method of fatigue life prediction formulated in this way is expected to describe the behavior of materials under thermo-mechanical fatigue.

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Pod kontrolą specjalistów

Nowa Energia

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2008

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nr 5

76--78

PL

W energetyce nie ma miejsca nawet na najdrobniejsze błędy. Nie ma, bo być nie może. Stawką jest tu ludzkie bezpieczeństwo. Dlatego tak ważna jest odpowiednio prowadzona kontrola jakości elementów wykorzystywanych w energetyce na każdym etapie ich produkcji. Jedna niepozorna rysa może zniszczyć projekt wart setki milionów złotych. Jedna niedostrzegalna gołym okiem skaza może doprowadzić do śmiertelnego zagrożenia.